Git excluding & including

It traps me a lot.

Ever I just known setting some wildcard patterns in .gitignore to exclude useless files.

If some object files( .o ) are in a lot of dirs with different depth, 

like a/a.o, a/b/b.o, a/b/c/c.o

then I have to set 

*/*.o

*/*/*.o

*/*/*/*.o

in .gitignore

Oh, it's a nightmare.

.git/info/exclude is the very file to achieve that.

*.o is enough.

In some circumstances, we need a few including from the excluding type,
set a ! (bang) at the beginning of the name.


A clear instance from gitignore manual page:

    $ git status
    [...]
    # Untracked files:
    [...]
    #       Documentation/foo.html
    #       Documentation/gitignore.html
    #       file.o
    #       lib.a
    #       src/internal.o
    [...]
    $ cat .git/info/exclude
    # ignore objects and archives, anywhere in the tree.
    *.[oa]
    $ cat Documentation/.gitignore
    # ignore generated html files,
    *.html
    # except foo.html which is maintained by hand
    !foo.html
    $ git status
    [...]
    # Untracked files:
    [...]
    #       Documentation/foo.html
    [...]